I have a simple solution for this: I set the "Album Artist" to "Various Artists" (you could also use "Compilation") while setting the "Artist" to the song's actual performer.

"Various Artists" is how I've always done it but to be honest I don't like it as I look from music by Artist/Album folder structure. With a few albums I have experimented altering the artist field to include the album name hyphen artist name, which has worked better for me since I tend to look via artist first. For example the format string %album-artist% - $num(%track%,2) - %title% versus %artist% - %album% - $num(%track%,2) - %title%